Notes from the Class – week of 10 December 2018

Now that I am back in front of classrooms, teaching AWS courses, it is time for the Notes from the Class blog posts to return. The nature of AWS means that every class I teach will have questions that I cannot immediately answer, these posts will allow me to share the questions and answers with students.

Does an object URI change as an S3 lifecycle policy migrates from S3 to Glacier?

Are the options for non-Windows/Linux operating systems with EC2?

AWS provides AMIs for Windows and various Linux distributions to create EC2 instances. According to the EC2 Features page “You are also empowered to use our bundling tools to upload your own operating systems.” However, I have not been able to find any reference to operating systems other than Windows and Linux, including on the AWS Server Migration Service page and the EC2 Features page. Even the EC2 Bare Metal service might be an option as it is a bare metal physical server option using I3 instances, I still haven’t found any reference to using alternative operating systems but you can run Hyper-V on I3 bare metal if that is what you need.

Are there Professional Services with Database Migration Services that will also migrate my applications?

When RDS fails over to a replica, can we choose which replica?

I think we may have got RDS Multi-AZ and RDS Read Replicas confused, particularly since Aurora, MySQL, and MariaDB combine features of the two. There are too many options to go through here, you would need to research the specifics for your requirements.

What are the options for cross-region RDS replication?

Up to 5 read replicas are available for MySQL, MariaDB, and PostgreSQL and 15 read replicas for Aurora, you can place a read replica in a different region. The other RDS database engine options do not support read replicas, so you could use the Database Migration Service in continuous mode to get data to another region. Keep in mind that read replicas are updated asynchronously, so replica data may be out of date by a few seconds. Also, remember that data transfer between regions is charged, so there needs to be business value for the additional cost.

VPC data transfer costs

Pricing for network transfers is complex on AWS and depends on which service is transferring data. It is worthwhile reading over the whitepaper “How AWS Pricing Works” spending some time with the Simple Monthly Calculator to see the cost effects of different usage. Then take a look at the EC2 Data Transfer pricing page, there is information about how data transfer is charged between regions, as well as VPC peering transfers within a region.